Drying



1,631,0Z May 1927' F. GREWIN DRYING Filed. Jan.l8, 1927 4 Sheets-Sheet 1 May 31 1927.

. 1,631,026 F. GREWINY DRYING Filed Jan. l8, 1927 4 SheetsSheet 3 Z men/60w:

F. GREWIN May 31 1 927.

DRYING Filed Jan. 18, 1927 4 Sheets-Sheet 4 -INVENTOR BY 494 I ATTORNEYS Patented. May 31, 1927.

UNITED" STATES- PATENT OFFICE.

FREDRIK ennwm, or 1103330211111, swnnnn, ASSIGNOR r0 mnnrcnn von'n coirrao'r COMPANY, mconronnrnn, on NEW YonK, N. Y., A CORPORATION or mew YORK.

name.

Application filed January 18, 1927, Serial No. 161,905, and in Sweden October 24, 1928.

This application is filed to replace and as a continuation in part of my copending application Serial No. 745,715flled in the United States on October 24, 1924 and in Sweden on October 24, 1923 and is to be considered as relating back thereto for common subject matter.

My invention relates to drying and more particularly to the drying of a web of sheet material such as paper, cardboard, pulp, etc., carried over a series of cylinders.

One purpose of my invention is to remove vapor' given ofl by the material to be dried from the vicinity thereof to obtain an eflective drying. A further purpose is to eject vapor laden fluid from the vicinity of the material to be dried by means of a streaniof fluid other than that ejected, the ejecting fluid thus avoiding contact to as great a degree as'is possible with the material to be dried. Still another purpose is to provide a drier for web material such as paper which. gives a better product than has hitherto been obtained.

My invention consists, in oneform, in'a method and apparatus for drying wherein a thin current of fluid such as compressed air is directed at high speed parallel to the surface to be dried but at a somewhat substantial distance therefrom so that the current does not impinge upon the surface and a second fluid such as atmospheric air is caused, by the ejector action of the said current of fluid, to pass between said current and said surface to dry the surface.

,In another form, I induce' atmospheric air into a high ressure stream of air within a directing tu and cause the pressure air and induced air to pass close to and paral- -lel to drying surface at high speed.

Further objects and features and the advantages of my invention will be understood as the description proceeds which is to be taken in connection with the accompanying drawings of which:

Fig. l'is a diagrammatic showing in elevation of a web drierillustrating a basic principle of my invention;

Fig. 2 is a plan view of the drier of Fig.

1 with the upper felt removed and with a part in section and showing means for heating and compressing the ejector fluid;

chine,

if unventilated would become m1xture of a1r, vapor and con 3 is a section taken on line, 3-3,

Fig. 5 is an end elevation showing the relative arrangement of the cylinders and the compressed air ducts; Fig. 6 is-asection of a nozzle; .Fig. 7 is a view showing the nozzle of Fig. 8 positioned in a mixing member having adjustable ports forv air; 1g. 8 is a sectidn on the line 1010 of Fig. 9;

Fig. 9 is a section of a modified form of nozzle; and

Fig. 10 shows a shield arrangement for use with the present invention.

Referring more particularly to Fig. 1 10 designates the upper set of drying cylin ers of a web drying machine and 11 designates the lower cylinders of the web drying ma said cylinders having the web 12 passed around them. An upper felt 13 passes over the upper cylinders 10 and around idler rolls 14. A lower felt 15 passes around cylinders 11 and idler rolls 16. The arran ement of ,the cylinders, the web and the elts provides a series of spaces extending laterally of the web drying ma-- chine, some of these spaces 17 being formed between sides determined by the web, the lower cylinders 11 and the upper felt' 13,

.while other spaces .18 are formed between sides determined by the web, the upper cylinders' 10 and the lower felt 15. The cylinders 10 and 11 are heated in known manner. Theweb of material to be dried gives off considerable moisture which tends to collect in the spaces 17 and 18. These spaces ockets for a ensed water, through which the web of material has to pass. In order to removethe moisture rom the spaces 17 and 18 and prevent conejectors directed in opposite directions into alternate spaces, The ejectors comprise small mouth pieces 19' and 20 so formed as to be able to direct a thin stream of fluid through the respective spaces without having the stream impinge upon the material to be dried. The ejector mouth pieces are T-densation of water, I provide a series of I as above described, parallel to the surface formed so that when supplied with fiuid at plied to the e ectors at such pressure that theai-r conta ns a relatively high speed in rectmg tube or conduit 36. Conduit 36 has of-slots 38 in the same'near the the mouth pieces and the eected stream becomes continuous and straig t.

In order to supply fluid-to the e ectors,

air conduits 21 and 22 (see Fig. 2) are'arran ed longitudinally, one along each side.

To conduit" 21 are oft e drying machine.

of upconnected-mouth pieces 19 by means wardly extending conduits 23. To conduit 22 are connected mouth pieces 20 by means of'upwardly extending conduits 24. Thus the ejectors comprisin mouth pieces 19 are directed in one direction into one alternate set of spaces 18 while the ejectors comprising'mouth pieces 20 are directed into the other set of alternate spaces 17 in the'opposite direction. By this means a more even drying of the web is obtained. Air is supto conduits 2-1 and 22 by means of pli 25 driven by any suitable prune compressor mover 26. The air supplied to the ejectors is preferably preheated as for example by the ar-. rangement indicated at 28 which includes a steam heating element 27 situated in an air chamber to which air is supplied from any desired source and from which heated air passes to compressor 25.

. By directing a thin stream into a space,

between thestream and the surface to be dried, which air serves'to dry the web and remove moisture. The stream withdraws moisture without "necessitating that the amount 'ofair supplied for obtaining the e'ector effect be large enough to be able to a slprb all the moisture given off from the we If desired, mouth pieces 29 below felt 15 may also be used to dry the felt.

or purposes of illustration, in Fig. 2, the middle cylinder is broken away to show the stream below the same ejected from mouth piece 19.

Figs. 4 to 9 show the invention as applied in actual commercial use. The cylinders 10 and 11 are rotated by means of intermeshing gears 30, 31, suitably supported on a framework 32. Figs. 4 to 9 show forms-of apparatus for applying the invention" to practice in'prcferred manner. In Fig. 4, 21 designates a supply conduit for air under highpressure corresponding to the like lettered conduit of Fig. of which one is designated by reference '-zle 35, shown in 35 isq'curved and ing 44 in a r a series 2. A series of pipes character; 33 in Fig. 4 are branched off from conduit 21. At the end of pi e 33 is anozsection in ig. 6. Nozzle I I tapers to a small end opening 4l'wh'ich passes through an end openmixing mem er 45 (Fig. .7

formed in part by the end of a straight dinozzle' end and a regulating sleeve 37 havingacorresponding series of ports 39 surrounding conduit 36. Sleeve 37 may be rotated about conduit 36 to determine the extent of opening through slots 38 and ports 39. Thumb screw .40 serves .to maintain osition on sleeve 37 in proper adjusted ports 39 conduit 36@ As shown in Fig.

are rhomboidal in form 1n order to facilitate' close setting in conjunction with the rectangular slots the ports, however, may be of any form or size for properly effecting the desired regu-' lation.-

In operation, the heated compressed air enters each individual connecting pipe 33 from the main air conduits ,21 and passes through the outlet nozzle 35 into the directing tube 36, additional air being drawn in through slots 38 and ports 39 to mingle with the ejector air for properly drying the sheet of paper, pulp, etc. Directmg tubes '36 extend into spaces 17 beyond the edged the web in order to prevent curling of the edge of the paper. In applying the invention to-practice I extend the directing tubes 38; both the. slots and.

beyond the edge of the web from about 16 I to 20 inches. I

Fig. 9 shows a modified type of nozzle adapted to be inserted into opening 44 and attached to a horizontally disposed conduit, should the arrangement of the drier as a whole necessitate such construction or make it advisable.

Fig. 10 shows diagrammatically a three tier drier equipped with ejectors 19, 20 ac cording to the invention. I use a pressure of air of from 20 to 70 inches of water in my invention which causes a blast of very high velocity. This assures blowing the air and moisture clear It causes a high speed current of hot gas out of the exhaust ,end of each space which would tend to travel out into the room and might injure-operators. To divert the hi h velocity stream I place shields 50, 51 at t e pace outlets which are suspended from hoods 52 arranged above the drier cylinders. Shield 50 is formed to divert the stream into the hood. .Suction on the hood aids "the efiect. These shields save heat in dithrough the machine.

recting the issuing stream into the hood' which can be taken up in preheaters.

Experiments have shown, that with 'my ,invention, moist air in a web drying machine can be completely removed and the web dried fully anduniformly. By means of the invention, the capacity of a web drying machine can be considerably increased without increase of steam consumption. On the contrary, with the invention it is. possibleto decrease the steam consumption.

My invention thus produces uniform drying of the whole of the web course, increase of capacity of the machine and reduced steam consumption per unit of weight.

While I have described various forms of my invention, it is t6 be understoodthat I shall not be limited to the specific embodiments illustrated.

Having thus particularly described my invention, what I claim is:

1. In combination, a plurality of cylinders over which a web of material to be dried is carried, the cylinders and web forming laterally extending spaces of uniform cross-section with open ends, and means to direct a single thin current of air at high speed through each of said spaces in direction substantially along the center lines of said spaces. V

In combination, a plurality of members over which a web of material to be dried is carried, the members and web forming spaces, an ejector directed into at least one of said s aces and formed to direct a thin stream 0 fluid through said space without impinging on said web, and thereby to induce a second fluid to pass through said space between said stream and the web, and means to supply air to said ejector.

3. That improvement in the art of drying a surface which consists in directin a thin current of fluid at high speed are. lel to said surface at a distance there rom so that said current does. not impinge. upon said surface, and thereby causing a second fluid to passbetween said current and said surface to dry the surface. 4. That improvement in the art of drying a web of material carried over members arranged to form a space between parts of the web, which consists in directing a thin current of air through the space in such direction as to avoid impinging on the web and thereby causing a second current of-air to pass between the directed current and the we to dry the web.

5. In combination, a plurality of members over which a web of material to be dried is carried, the members and web formin spaces with laterally extending sides and open ends and means to direct a single thin current of fluid of high velocity through each of said spaces in direction parallel to said laterally extending sides. 6. In combination, a pluralit .ofmembers over which a web of materia to be driedv is carried, the members and web forming spaces, ejectors situated at the ends of the spaces and arranged to. deliver a current of fluid of high velocity into each of the spaces in direction so as to pass entirely throughthe spaces and not impinge upon the web and means to supp'ly'pressure fluid to said ejectors, so that a current-of fluid other than t at discharged through the ejectors serves to dry the web. 1

7. In combination, a plurality of members over which a web of material to be dried is carried, the members and web forming spaces with laterally extending sides and open ends, a plurality of small-mouthed e ector pipes, one directed into'each of said s aces and formed to limit the spread of t e stream of ejecting fluid expelled therefrom, each pipe being directed to discharge a single stream of fluid of high velocity through the space into which it is directed, parallel to said laterally extending sides, and means to supply air to said ejector pipes. a

8. Incombination, a web drier comprising a lurality of members over which a web 0 material to" be dried is carried, the

members and web forming a series of spaces, a series of ejectli'rspositioned on one side of said drierand directed into one set of alternate spaces, a second seriesof ejectors posited on the other side of said drier and I directed .into the other set of alternate Spaces and means to supply air to said ejecors. 9. In combination, a web *drier comprising a plurality of members over which .a web 'tolbe dried is carried, the members and web forminglaterally extendingspaces, a series ofejectors posited on one side of said drier, and directed into one set of alternate spaces, said ejectors being formed to direct a thin stream of fluid through the respective s aces without impinging on said 'web, and t ereby to induce a second fluid through the spaces between said stream and the. web to dry the web, a second series of e ectors I posited on the other side of said drier directed into the other set of alternate spaces and means to supply air to said ejectors. 10. In combination, a plurality" of mem hers-over which-a web of material to be dried'is carried, the members and web formlng spaces with laterally extending sides and.

open ends and means to direct thin currents of fluid through said spaces in direction parallel to said laterally extending sides and at a substantial distance from "said sides so that a diflere'nt fluid than. that of the currents may be induced between the currents and the'laterally extending sides,

.11. In combination, a plurality of cylinders over which a web of material. to be dried is carried, the cylinders and web form-- ing laterally extending s aces of uniform cross section with 0 en en s, means to direct a thin current of air at high speed through each of said 'spaces in a direction substantially along the center lines of said spaces, and means permitting said thin current of air to induce the flow of a regulated quantity of additional air.

12. That improvement in the art of drying a surface which consists in directing a current of compressor air of high pressure parallel to said surface at a distance therefrom and parallel thereto and inducing at-' mospheric air to ass past said surface'due to ejector effect of said current.

13. In combination, bers over which aweb of material to be dried is carried, the members and'web forming spaces, directing tubes extending into said spaces beyond the edge of the Web, ejectors arranged to discharge into said directing tubes and nieans to supply fluid to said 'ejectors; I,

14. In. combination, a plurality of members over which a web of material to be dried is carried, the members and web form-- ing spaces, directingtubes having openings at both endsgand extending into said spaces beyond the edge of the Web, ejectors arranged to discharge into said directing tubes and to draw air through some of said openings and means to supply air at high pressure to said ejectors. 15. In combination, a plurality of mema plurality of mem-' into said hood. 1 r

- signature.

bers over which aweb of material to be dried is carried, the members and web forming spaces, directin tubes extending into said spaces beyond It e edge of the web and having air openings, discharge into said directing tubes and to draw air through said openings, means to supply air at high pressure to said ejectors and means to regulate the supply'of air.

ejectors arranged to 16. A drier comprising, in combination,

a series of cylinders for carryinga web of "material t0-= be dried, the cylinders and the web forming laterally extending spaces with open ends, a hood above said drier, ejectors directing streams issuedfrom said ejectors 17 In combination, a plurality, of members over which a web of material to be dried v is carried, the members and web forming spaces, ejectors extending :into .said spaces beyond the edge,of the Web and arranged situated at the ends of the spaces, means to I supply air at high pressure to said ejeetors and shields suspended from saidhoods for to deliver a current of fluid. of high velocity into each of the spaces and means to supply.

fluid to said ejectors,

In testimony whereof I hereunto aflix my FiinnR K GREWIIT'. 

